Temperature responsive switch



TEMPERATURE RESPONS IVE SWITCH Filed Sept. 12, 1955 INVENTOR.

[77-5 ATTORNEYS,

Patented Mar. 23, 1937 PATENT OFFICE TEMPERATURE RE SFONSIVE SWITCHBruno Radtke, Chicago, Ill., assignor to Exhibit Supply Company,Chicago, 111., a corporation of Illinois Application September 12, 1935,Serial No. 40,199

2 Claims.

This invention relates to a temperature-responsivc switch.

It is an object of this invention to provide an improvedtemperature-responsive switch which is relatively simple and inexpensivein construction and efficient in use.

Among the several objects of the invention is the provision of a noveltemperature-responsive or thermostatic switch used in connection withelectrical equipment where there is a possibility that the electricalapparatus may, during the course of operation, stick or stop and createa high current flow in the line and a consequent possibility of burningout some of the electrical apparatus, batteries or the like; or wherethere is a possibility of running the same down; the object of thisinvention being to provide a novel temperature-responsive switchvwhereby whenever an excessive current fiow is set up in the line, theswitch will automatically open and thereby open the circuit in the line,thus protecting the electrical apparatus which may be arranged therein.

Other objects will appear hereinafter.

25 The invention consists in the novel combination and arrangement ofparts to be hereinafter described and claimed.

The invention will be best understood by reference to the accompanyingdrawing showing 30 the preferred form ofconstruction, and in which:

Fig. 1 is a vertical sectional view showing a preferred form of thepresent invention;

Fig. 2 is a bottom plan view taken on line 2-4 in Fig. 1, and

Fig. 3 is a schematic wiring diagram illustrating the present inventionin one of its typical uses.

In the operation of electrical devices in which there are movingparts-some of these may de- 40 velop a tendencyto bind or stick and thuscreate a condition in the circuit wherein the current fiow becomesexcessive, causing a temperature rise in the conductors or in themechanism in circuit,

' and thereby cause a drain on the source of 45 energy, and there alsois a possibility that some of the equipment may also become over-heatedand be ruined.

To prevent the difilculties enumerated above,

I have provided a temperature responsive switch 50 which is generallyindicated at ID. This switch Ill has a central metal strip II, andformed integrally with the strip H is a metal contact I2 which isthreaded, as at H, so that it may be.

adjusted relative to a movable contact H, the 55 contact l2--I3 having aslot l5 formedin one end thereof so as to facilitate the adjustment ofthe contact I2 relative to the movable contact l4. Also threaded uponthe body I3 is a'locking device in the form of a nut IS.

The movable contact I! is mounted upon a bi-metallic strip of metal I'l,this bi-metallic strip I] being composed of two thin strips l8 and IQ ofmetal of different compositions held together in close relationship soas to form a. unitary member. This strip [1 is mounted upon a base bymeans of a rivet or the like 2|.

Separating the metal strip H from the base 20 is an insulating member 22which may be composed of fibrous material, hard rubber, or the like, andthis member 22 has a small raised portion 23 which is fitted into theopening 24 of the strip II. The members II and 20 are fastened togetherby means of screws or the like 25, the head 26 of the screw beinginsulated from the member I l by another strip 21 of fibrous material,hard rubber, or the like 2|, 'and this strip 2'! is also provided withraised portions 28 which are fitted into the opening 24.

An electrical conductor 29 is fastened to the metal strip II by means ofa metal screw or they like 30, current thus passing from the conductor29 through the screw 30 into the strip II and through its contact pointl2, through the movable contact point l4, the bi-metallic strip [1, thebase20, the screw 25, and back through the conductor 3|, the presentswitch being thus connected in series in the circuit 32 (Fig. 3) whichshows diagrammatically how the switch I0 may be connected in series in atypical circuit 32,

' which may include a motor or some other electrical mechanism 33, andalso a source of energy in the form of a battery .or the like 35; itbeing understood that the present switch I0 may be used in conjunctionwith any type of electrical apparatus.

It has been found that frequently 'when an electrical mechanism is inoperation, the same will inadvertently stop and cause a dangerous risein current in the circuit, and when such a contingency arises, thesource of current 35 may be drained or the motor or other apparatuswhich may be embodied in the circuit may be burned out.

When such a contingency arises in the use of -the present protectiveswitch, the excessively heavy current passing through the circuit 32causes the bi-metallic strip I! to become heated the latter beingdimensioned for predetermined loads or currents, and due to thedifference in the expansionco-eflicients of the metals l8 and l9, thebi-metallic strip I1 is caused to expand (from full line to dotted lineposition, Fig. 1), thus separating the contact points l2 and M, andthereby opening the circuit 32. The circuit 5 32 being thus openedremoves the load from the line. When the bi-metallic strip ll coolsthere being no current flow to heat it, the circuit 32 is again closedat that point since the strip l1 will return to its normal closedcircuit condition, whereupon the operation of the mechanism may beresumed.

, While I have illustrated and described the preferred form ofconstruction for carrying my invention into effect, this is capable ofvariation and modification without departing from the spirit of theinvention. I, therefore, do not wish to.be limited to the precisedetails of construction set forth, but desire to avail myself of suchvariations and modifications as come within the scope of the appendedclaims.

Having thus described my invention, what I claim as new and desire toprotect by Letters Patent is:

1. A thermostatic switch for use with game apparatus and comprising asubstantially elongated arm having a pair of oppositely directedorificed side wings extended from its sidesintermediate its longitudinalextremities, said wings being bowed adjacent the juncture with saidelon- 3 gated arm to raise the latter above the plane of the wings, anelongated bi-metallic contactor extended from and secured to one of thelongitudinal extremities of said arm, a second elongated.

contact arm insulated from and secured to said first arm, said secondarm having an angled end portion overlying said bi-metallic member, an

adjustable contact member threaded through said angled end portionadjacent the outermost extremity thereof and threadable toward and awayfrom said bi-metallic member, together with means including a memberthreadable onto said adjustable contact member and against saidlastmentioned arm to lock said adjustable contactor in position.

2. Athermostatic switch for use with game apparatus and comprising asubstantially elongated arm having a pair of oppositely directedorificed side wings extended from its sides intermediate itslongitudinal extremities, said wings being bowed adjacent the juncturewith said elongated arm to raise the latter above the plane of thewings, an elongated bi-metallic contactor extended from and secured toone of the longitudinal extremities of said arm, said extremity beingtapered in a direction toward its juncture with said bi-metalliccontactor, a second elongated contact arm insulated from and secured tosaid first arm, said second arm having an angled end portlon overlyingsaid bi-metillic member, an adjustable contact member threaded throughsaid angled end portion adjacent the outermost extremity thereof andthreadable toward and away from said bi-metallic member, together withmeans including a member threadable onto said adjustable contact member'and against said lastmentioned arm to lock said adjustable contactor inposition, and said second contact arm having an elongated tapered tailportion at its extremity opposite said angled end portion and extendedbeyond the underlying extremity of said firstmentioned contact arm.

' BRUNO RADTKE.

